On March 28, the U.S. Supreme Court hears arguments in the Gloucester County School Board case, its first encounter with the growing transgender rights movement.

Journalists, it's time to work up those walkups.

The basics: The Obama administration’s Departments of Education and Justice notified all U.S. public schools last May that to qualify for continued federal funding they need to follow each student’s sense of personal “gender identity,” as opposed to birth biology, regarding access to “sex-segregated restrooms, locker rooms, shower facilities, housing and athletic teams (.pdf document here)."

That change redefined “sex” under Title IX of the anti-discrimination law in question. For 44 years before that, the government thought “sex” meant biological gender, not an identity that may conflict with it. In the current case, an anatomically female Virginia high schooler who is transitioning wants to use boys’ toilets instead of unisex facilities the school provides. Local school districts are caught between transgender rights appeals and community concerns about privacy and security.

The case’s significance is not ended by the February 22 decision of the incoming Donald Trump administration to rescind the Barack Obama directive for now. Access to locker rooms and showers are also part of this hot-button debate.

With gay marriage legalized throughout the United States by the Supreme Court, the LGBTQ movement is focusing all its moxie on transgender rights. The belief that gender is “assigned” at birth but flexible, rather than fixed by biology, gains cultural clout from important segments of the Democratic Party, big business, the academic world, the entertainment industry, professional and college athletics, and the like.

That poses a major challenge for advocates of religious liberty, already on the defensive with other issues.

A major chunk of U.S. organized religion has now reacted in unison against the Obama policy. A “friend of the court” legal brief in the case (.pdf document here) allies the nation’s two largest denominations, the Catholic Church and Southern Baptist Convention, with the National Association of Evangelicals, Lutheran Church–Missouri Synod, Union of Orthodox Jewish Congregations of America and Church of Jesus Christ of Latter-day Saints (the Mormons). The filing also cites support from authoritative teachings of monotheistic Orthodox Christianity, Islam and Sikhism (Buddhism and Hinduism are not mentioned).

The brief says varied religions have “remarkable unanimity on the origin and purpose of gender as immutable and divinely ordained.” It states that both religious teaching and “practical experience” show that “gender is a given, consisting of attributes intrinsically connected with one’s birth sex -- not an individual choice," though noting certain medically anomalous cases.

The group is concerned that change in federal policy would “provoke serious religious conflicts,” especially for schools and colleges and potentially for many other organizations.

As of this writing, no denomination has filed a brief providing religious backing for the transgender rights side. There the most important brief was filed February 23 by the American Civil Liberties Union. It says “targeting” such as the Virginia school performed “humiliates and stigmatizes” transgender students, causing a “devastating impact on their physical and mental well-being and their ability to thrive in school.”

In other court filings, a group of religious colleges objects that the Obama administration ignored the statutory rule-making process of “notice and comment” needed for such policy changes. For that and other reasons, the Trump team contends that the legal issues involved need further consideration, a point some leading law professors make in filings.

The Trump administration also thinks that states and local schools should take “the primary role” in setting educational policy. That’s similar to contentions in the brief filed by the associations that represent the nation’s 10,000 school superintendents and 90,000 local school boards. A related issue is whether federal judges and agencies have the power to settle social issues, rather than the U.S. Congress and state legislatures.

Meanwhile, psychiatrists and other professionals are debating whether surgery or hormone treatments are appropriate for youths with “gender dysphoria,” in some cases involving children in elementary school.